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IEEE International Conference on Plasma Science (ICOPS)

作者： Yuan Fu YuBin Yue Xian X. Lu State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan Hubei CN State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan Hubei China

Summary form only given. Ring-shape is one of the feature characteristics of plasma bullet. However regarding the mechanism of the ring-shape structure of the plasma bullet, it is still not clear. In this paper, a series of special designed experiments are carried out to investigate the mechanism of the ring-shape structure of the plasma bullet. The typical ring-shape structure can be seen in Fig. l. In these experiments, the effect of the surface discharge and the effect of the surrounding gas diffusion are studied, thus the effect of Penning ionization can be separated. lt is found that both the diffusion of the surrounding air and the surface discharge play important roles in the forming of the ring-shape structure.

关键词： Plasmas Shape Surface discharges Discharges (electric) electromagnetics Ionization Plastics

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High-speed sensor head with wide frequency range using deformed helix ferroelectric liquid crystal

High-speed sensor head with wide frequency range using defor...

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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： Q. Guo Huijie Zhao V. G. Chigrinov H. S. Kwok Z. Brodzeli School of Instrument Science and Opto-electronics Engineering Beihang University Beijing China State Key Lab on Advanced Displays and Optoelectronics Hong Kong University of Science and Technology Hong Kong School of Electrical Engineering and Telecommunications University of New South Wales Sydney NSW Australia

ISBN: (纸本)9781509033331

In this paper we propose a new approach to fiber-optic sensor head based on voltage-controlled ferroelectric liquid crystals (FLC). Using nano-grid electrodes, nanometer-scale photo-alignment layers and deformed helix ferroelectric liquid crystals with a sub-wavelength helix pitch of 150 nm, we have realized a fully integrated polarization-based photonic transducer which exhibits fast response to an applied voltage/electric field, excellent linearity and allows multiplexing using standard, low cost telecom optical fibers. In addition, the electro-optical behavior of deformed helix ferroelectric (DHF) liquid crystal in reflective mode is described and tested. The electrically controlled reflectance has been measured at sub-kilohertz driving voltage frequency for different polarizations of the incident light and compared quite successfully with the simulation results.

关键词： Liquid crystals Photonics Reflectivity Frequency measurement Electrooptic effects Optical fibers Voltage measurement

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Research of stator displacement technique in multistage axial-flux permanent magnet machines

Research of stator displacement technique in multistage axia...

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International Conference on Magnetics (INTERMAG)

作者： X. Wei K. Yang State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology WuHan

Axial flux permanent-magnet machines have gained popularity in the last few decades because of their higher torque at low speed and better power density compared with radial flux machine, moreover, due to its inherently short axial length, they find applications where the used conventional PM machines are not appropriate, such as hybrid traction motors. However, the major undesired effects are the cogging torque due to high frequency flux pulsation caused by air gap reluctance variation and the lack of field weakening capability due to a fixed magnetic excitation which limits the drive's maximum speed and becomes a significant limitation for both radial and axial flux PM machines. In this paper, a new multistage axial flux permanent magnet will be proposed, and based on the multistage axial flux permanent magnet synchronous machine (M-AFPM), the stator displacement technique will result in a multi-phase machine with little mutual inductance between two stators and improve the torque density and quality, moreover, it can reduce the cogging torque by half at best, and a new switch-phase connection technique combine the stator displacement is proposed for extending the flux-weakening capability. The performance of the multi-phase M-AF-PM will be studied in this paper by the 3D-FEA. Based on a 2kW-1000rpm 10-pole 12-open-slot prototype with stator displacement, the experimental study will is developed. And the comparison between the experiments and 3D-FEA results will be proposed in this paper.

关键词： Stator windings Torque Forging Switches Synchronous motors Switching circuits

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A control method for permanent-magnet synchronous motor with unbalanced cable resistor

A control method for permanent-magnet synchronous motor with...

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International Conference on Power Electronics Systems and Applications (ICPESA)

作者： Zou Xunhao Shenghua Huang Qin Zhuqian Xiaodong Hu Kan Guangqiang State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology China

ISBN: (纸本)9781509000647

The three phase cable connecting the inverter and PMSM may be unbalanced in some situation such as the deep drilling platform. This paper presents the mathematical model of PMSM with unbalanced cable resistance. The traditional PI current regulator cannot work well within the situation. The hysteresis band controller can operate well because it's independent of load parameters but the switching frequency may be very high to get good performance, which is not suitable. So a novel proportional integral resonant controller is proposed to eliminate the harmonic current caused by the asymmetry of the stator resistance. From the results of the experiment, the mentioned control strategy proves to be appropriate for PMSM with unbalanced cable resistance.

关键词： Immune system Switches Resistors Analytical models Yttrium Space vector pulse width modulation

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Vernier reluctance dual-stator inner-rotor machines with semi-closed slot

Vernier reluctance dual-stator inner-rotor machines with sem...

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International Conference on Electrical Machines and Systems (ICEMS)

作者： Linyuan Xiao Jian Li Ronghai Qu Dawei Li Yuting Gao State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology China

ISBN: (纸本)9781479988068

This paper proposes vernier reluctance dual-stator machines with semi-closed slot. The structure of vernier reluctance dual-stator machines with semi-closed slot is firstly given, followed by a comprehensive comparison with the conventional structure in aspects of no load flux linkage, cogging torque and torque. The effect of inner stator shift on the performance of vernier reluctance dual-stator machines with semi-closed slot is also analyzed.

关键词： Torque Stators Couplings Forging Decision support systems electromagnetics Reluctance machines

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A novel axial flux switched reluctance motor with grain oriented electrical steel

A novel axial flux switched reluctance motor with grain orie...

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International Conference on Magnetics (INTERMAG)

作者： J. Ma R. Qu J. Li State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan

Switched reluctance motor (SRM) has been widely used in automobile and aerospace for its fault tolerance and simple construction [1]. According to the direction of magnetization, SRM can be classified as radial flux and axial flux types. Axial flux switched reluctance motor (AFSRM) with its flat shape and high aspect ratio is regarded to be suitable for in-wheel motor applications. An axial flux segmented rotor-switched reluctance motor topology is suggested in [2] to increase active surface area for the output torque within a confined space. However, torque and efficiency of the AFSRM are less than those of PMSM for the same frame size. To solve above problems, grain oriented electrical steel (GOES) could be used for AFSRM to improve the electromagnetic properties because the material has a good magnetic characteristic in the rolling direction. A design of AFSRM for traction application was proposed in [3]GOES has been used in stator to reduce leakage flux, divided segments in c-core structure may be a challenge to the joint strength of the structure.

关键词： Stators Steel Reluctance motors Rotors Torque electromagnetics Topology

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New Current Control Method of DC Power Supply for Magnetic Perturbation Coils on J-TEXT

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Plasma Science and technology 2014年第11期16卷 1074-1078页

作者：曾武兵丁永华易斌许航宇饶波张明刘明海 State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology

In order to advance the research on suppressing tearing modes and driving plasma rotation, a DC power supply （PS） system has been developed for dynamic resonant magnetic perturbation （DRMP） coils and applied in the J-TEXT experiment. To enrich experimental phe- nomena in the J-TEXT tokamak, applying the circulating current four-quadrant operation mode in the DRMP DC PS system is proposed. By using the circulating current four-quadrant oper- ation, DRMP coils can be smoothly controlled without the dead-time when the current polarity reverses. Essential circuit analysis, control optimization and simulation of desired scenarios have been performed for normal current. Relevant simulation and test results are also presented.

关键词： DRMP power supply （PS） J-TEXT four-quadrant operation

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Pole ratio effect on performance of stator DC excited vernier reluctance machines

Pole ratio effect on performance of stator DC excited vernie...

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International Conference on Magnetics (INTERMAG)

作者： S. Jia R. Qu J. Li State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan

The novel vernier reluctance machines with DC field winding in stator (DC-VRMs) have the advantages of wide speed range due to the flexible exciting field by DC winding, robust rotor structure thanks to no PMs or windings on rotor similar to doubly salient machines. In this digest, the effect of ratio of rotor poles to stator armature winding poles on the electromagnetic performance, such as back-EMF, torque and torque ripple and so on are researched based on six machines, which stator/rotor slot number are 12/7, 12/10, 12/11, 12/14, 12/16, 12/17, respectively and the corresponding pole ratio are 7/1, 10/4, 11/5, 14/4, 16/2 and 17/1, respectively . It is found that, the average torque is mainly determined by the ratio of rotor poles to stator armature winding poles in a certain region . For torque ripple, it is mainly affected by the least common multiple (LCM) of the number of stator and rotor slots . For example, 12/17 exhibits the lowest (1 .4%) while the 12/16 is largest (80%) .

关键词： Windings Stator windings Rotors Torque Reluctance machines

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A novel initial rotor position detection method for PM synchronous motors

A novel initial rotor position detection method for PM synch...

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International Conference on Power Electronics Systems and Applications (ICPESA)

This paper presents a novel initial rotor position estimation method for PM synchronous motors in EV application based on high frequency voltage injection. Mathematical model of PMSM are presented. Instantaneous current value rather than the amplitude of the corresponding current is utilized to calculate the rotor position. The filter to get the amplitude of the current is not needed and the accuracy of the result is irrelevant with the amplitude and frequency of the injected voltage. From the results of the experiment, the mentioned technique proves to be appropriate for initial rotor position detection of PMSM.

关键词： Synchronous motors Rotors Saturation magnetization Biographies Generators

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Plasma Response to Supersonic Molecular Beam Injection in J-TEXT

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Plasma Science and technology 2014年第1期16卷 17-20页

作者：肖金水杨州军庄革胡启明冯先德刘明海 State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology

Recently, hydrogen fueling experiments with supersonic molecular beam injection （SMBI） system have been performed in the J-TEXT tokamak. To evaluate the effects of the in- jection amount of SMBI on plasma behaviors, moderate and intensive SMBs have been separately injected and compared with each other in Ohmic discharges. With moderate SMBs, electron den- sity increases about twice as before, the size of magnetic island slightly decreases, and the edge toroidal rotation speed in a counter-current direction, measured by a high resolution spectrometer （Carbon V ion, 227.09 nm, r/a-= 0.7-0.8）, is accelerated from 8 km/s to 12 km/s. The state of higher electron density with moderate SMBI can be maintained for a long period, which indicates that plasma confinement is improved. However, with intensive SMBs, the accompanied magne- tohydrodynamic （MHD） activities are triggered, and the electron density increases moderately. The edge toroidal velocity is decreased, in certain cases even reversed in the co-current direction. The statistical result of experimental data for moderate and intensive SMBs suggests a preferred fueling amount （less than 3.2 ~ 1019） to improve the SMBI fueling efficiency in experiments.

关键词： SMBI fuelling plasma responses J-TEXT

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